1. Field of the Invention
The present invention relates to a heat-dissipating fan and more particularly to a heat-dissipating fan for lowering temperature of at least one heat-generating electronic element by mounting the heat-generating electronic element on a downstream side of the blades of an impeller of the heat-dissipating fan.
2. Description of Related Art
A conventional heat-dissipating fan, as illustrated in FIG. 1 of the drawings, comprises a housing 1, an impeller 2, and a circuit board 3. The housing 1 comprises an air channel 10, an air inlet 11, an air outlet 12, and a base 13, and further accommodates a stator 14. The impeller 2 is received in the air channel 10. Air currents enter the air channel 10 via the air inlet 11 and exit the air channel 10 via the air outlet 12. The circuit board 3 and the stator 14 are mounted on the base 13, which is mounted on the air outlet 12 side. The impeller 2 is coupled to the base 13 and comprises a hub 21, a shaft 22, a plurality of blades 23, and an annular magnet 24. The hub 21 is substantially inverted bowl-like. The shaft 22 extends from a center of an inner face of the hub 21 and is rotatably connected with the base 13. The blades 23 are annularly provided on an outer periphery of the hub 21. The circuit board 3 comprises a sensor 31 and at least one heat-generating electronic element 32 that controls alternate energizing of the stator 14. In operation, the annular magnet 24 drives the impeller 2 to turn based on the alternate energizing. Hence, the blades 23 drive air currents to flow from the air inlet 11 side to the air outlet 12 side.
The electronic element 32 such as a transistor that uses semi-conductive metal/non-metal blending material to control the gating direction of the electric current consumes electricity and generates heat. The electronic element 32 is generally mounted in a range of the base 13 and the hub 21 and lacks mechanism for dissipating the heat generated by the electronic element 32, resulting in excessively high temperature and adversely affecting operational stability of the electronic element 32 and even shortening the life of the heat-dissipating fan.